Self-contained biological indicator

ABSTRACT

A SCBI useful in ambient air pressure systems is disclosed. The SCBI includes a body which serves as the culture tube, a glass media ampoule, an inoculated stainless steel disc positioned on the top of the glass media ampoule so that the spores are close to the top/opening of the SCBI, filter paper on the top of the body and overlying the disc, and a cap.

RELATED APPLICATION

This is a divisional application and continuation application claimingpriority on U.S. application Ser. No. 16/688,341, filed Nov. 19, 2019,entitled “Self-Contained Biological Indicator,” which is a divisionaland continuation of U.S. application Ser. No. 15/381,948, filed Dec. 16,2016, entitled “Self-Contained Biological Indicator,” now U.S. Pat. No.10,513,678, issued on Dec. 24, 2019, and which claims benefit of U.S.Provisional Application Ser. No. 62/268,883, filed Dec. 17, 2015,entitled “Self-Contained Biological Indicator,” and which applicationsare incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates to biological indicators (BI) fordetermining the effectiveness of a sterilization and/or decontaminationcycle and methods of use thereof. More particularly, the invention isdirected to a self-contained biological indicator (SCBI) for use inmonitoring the sterilization/decontamination of isolator systems.

BACKGROUND OF THE INVENTION

The use of BIs for verifying the effectiveness of a sterilization ordecontamination cycle or process in healthcare, pharmaceutical, foodprocessing and related fields is known. Generally, certain sterilizationprocesses are used which include a pre-vacuum process to remove all ofthe ambient air from the sterilization chamber. Such processes are usedfor, among other things, medical instruments. In this process, thesterilization chamber is evacuated of all ambient air. This allows thesterilant to more readily reach all parts of the load including theinterior of a SCBI.

Another type of sterilization or decontamination process uses anisolator which sterilization/decontamination chamber may vary in sizefrom a few feet to a long tunnel. Such isolators do not remove all ofthe ambient air and are used for sterilizing or decontaminating theinterior of the isolator, including all furniture such as filling lines,assembly lines, etc. The isolators may include covered openings forinserting or removing the items to be aseptically filled and/orassembled. BIs are primarily used in this process during cycledevelopment and validation activities. Since these types of isolators donot remove all of the ambient air, the sterilant may not reach theinoculated carrier in certain SCBIs, e.g. where the carrier is locatedat the bottom or on the side of the SCBI. In such situations, the SCBImay not provide accurate results of the sterilization and/ordecontamination process. Accordingly, there is a need in the industryfor a SCBI for use in an ambient air isolator to provide accuratesterilization and/or decontamination results.

SUMMARY OF THE INVENTION

A primary object of the present invention is to provide SCBIs fordetermining the effectiveness of sterilization/decontamination cyclesand methods of use thereof.

Another primary object of the present invention is to provide a SCBIuseful in ambient air pressure systems. The SCBI of the presentinvention comprises a body which serves as the culture tube, a glassmedia ampoule, an inoculated stainless steel disc positioned on the topof the glass media ampoule so that the spores are close to thetop/opening of the SCBI, filter paper on the top of the body andoverlying the disc, and a cap.

These primary and other objects of the invention will be apparent fromthe following description of the preferred embodiments of the inventionand from the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description of the specific non-limitingembodiments of the present invention can be best understood when read inconjunction with the following drawings, where like structures areindicated by like reference numbers.

Referring to the drawings:

FIG. 1 is an exploded view of a SCBI of the present invention.

FIG. 2 is a partially assembled view of the SCBI of FIG. 1 .

FIG. 2A is a perspective view of one embodiment of filter paper.

FIG. 3 is the assembled SCBI of FIG. 1 with the cap in an open positionas used during a sterilization/decontamination process.

FIG. 4 is the assembled SCBI of FIG. 1 with the cap in a closed positionsuch as after the sterilization/decontamination process and prior toincubation.

FIG. 5 is a perspective view of the body of the SCBI of FIG. 1 .

FIG. 6 is a side view of the body of FIG. 5 .

FIG. 7 is a cross-section taken along line 7-7 of FIG. 6 .

FIG. 8 is an enlarged view of the upper portion of the body taken at aportion of FIG. 6 .

FIG. 9 is a top view of the body of the FIG. 5 .

FIG. 10 is a perspective view of the cap of the SCBI of FIG. 1 .

FIG. 11 is a side view of the cap of the FIG. 10 .

FIG. 12 is a cross-section taken along line 12-12 of FIG. 11 .

FIG. 13 is an enlarged view taken at a section of FIG. 12 .

FIG. 14 is a top view of the cap of FIG. 10 .

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1-14 , the present invention is directed to a SCBI 10comprising a body 12, a cap 14, a glass media ampoule 16, an inoculatedsteel disc 18, and filter paper 20. The SCBI of the present inventionmay be used in sterilization/decontamination of items in an ambient airsystem such as restricted access barrier systems (RABS) such asisolators and/or room fumigation applicators using various sterilants,including hydrogen peroxide gas, chlorine dioxide gas and nitrogendioxide gas. The SCBI is placed in an isolator chamber wherein thespecific items to be sterilized/decontaminated are situated to determinethe effectiveness of the sterilization/decontamination process. As seenin FIG. 3 , the SCBI may be in an open position subjecting theinoculated stainless steel disc 18 to the sterilant to determine theeffectiveness of the sterilization/decontamination process. After thesterilization/decontamination process, the SCBI is closed as shown inFIG. 4 . The glass media ampoule 16 is opened to release a growth media.A presently preferred growth media is a proprietary growth media of MesaLaboratories, Inc. comprising a formulated soybean casein digest culturemedium containing a color indicator which turns a dramatic yellow whenspores are present. Pressure is applied to the body 12 and the ampoule16 to break the ampoule and release the growth media to the closed SCBI.The SCBI is then placed in an incubator. After incubation, the SCBI isexamined to determine whether the sterilization/decontamination processhas been effective, i.e. are there any live spores.

Referring again to FIGS. 1-14 , the various components of the SCBIinvention will now be discussed. Body 12 includes a cylindrical sidewall 30, a bottom wall 32 enclosing the body, and a collar 34 joiningthe cylindrical side wall 30 by shoulder 36. The collar 34 extendsoutwardly of the side wall 30 and is adapted to receive cap 14. Collar34 includes an upper rim 38. Body 12 may be made of plastic such aspolypropylene.

Cap 14 may be in an open position or a closed position in relation tobody 12 as seen in FIGS. 3 and 4 . The cap 14 is adapted to move up anddown on the exterior of collar 34. On the outside wall of collar 34there are annular protrusions 38 a and 38 b which serve to mate with agroove of cap 14 to hold the cap in an open position or closed positionas discussed below. There are a plurality of ribs 40 in collar 34 whichprovide a number of functions, including providing strength and rigidityto body 12 and allowing for air flow of the sterilant down the side ofthe body towards the bottom of the body. A presently preferredembodiment includes twelve ribs. The ribs preferably extend outwardlyfrom inside wall 42 between rim 38 and shoulder 36 such that the outerface 44 of the ribs is flush or even with the inside of side wall 30.

Cap 14 includes a top 50, cylindrical side wall 52 and bottom 54. Thecap includes six apertures 56 through which the sterilant may enter theSCBI when in the open position. A preferred number of apertures is sixto eight. Cap 14 further includes on its interior portion a skirt 58which fits over body 12 by friction fit and is adapted to slidably moveup and down the exterior wall of collar 34 of body 12. The cap includesa groove 60 which will engage protrusions 38 a and 38 b of body 12 tohold the cap in an open position, protrusion 38 a engaging groove 60, orin a closed position, protrusion 38 b engaging groove 60. Cap 14 may bemade of plastic such as polypropylene.

Glass media ampoule 16 comprises an ampoule made of glass and which maybe rupturable upon applying pressure to sidewall 30 and ampoule 16. Theampoule includes a growth media 70. The ampoule fits snuggly in body 12,that is, it is loose in body 12 but allows for rupture of the ampoule asdescribed herein and seen in the Figures, and extends close to the topof collar 34 as shown, for example, in FIG. 2 and leaving sufficientspace to allow disc 18 to seat on ampoule 16 as discussed below andwherein disc 18 is seated below the rim 38 of collar 34. The growthmedia is used when testing the efficacy of thesterilization/decontamination process, i.e. during the incubationprocess to determine whether there are any live spores.

The inoculated stainless steel disc 18 comprises a disc made ofstainless steel, preferably a 9 millimeter stainless steel disc. Thedisc is dish shaped having an outer edge 80 and a central portion 82.The disc is inoculated with spores (not shown) such as G.stearothermophilus. A preferred disc is made by Mesa Laboratories andsold under the trademark APEX®. The disc is located on top of the glassmedia ampoule 16. As shown in FIG. 2 , the outside diameter of the discis of a smaller dimension then the inside diameter formed by the ribs 40such that when ampoule 16 is broken the disc will drop down into body 12to fully interact with the growth media.

Accordingly, the spores on disc 18 are close to the top/opening of theSCBI during the sterilization/decontamination process. This ensures thatthe sterilant reaches the disc 18 during a sterilization/decontaminationprocess in an ambient pressure system.

Filter paper 20 is located above the collar 34 and covers the inoculatedstainless steel disc 18. A preferred filter paper is Tyvek® paper. Thefilter paper may include a top portion 90 having a side wall portion 92which fits over the exterior wall of collar 34 of body 12. In apreferred embodiment, the filter paper 20 comprises a round planarstructure 20A as shown in FIG. 2A having a top portion 90A and coversthe top of the body 12 and the inoculated stainless steel disc 18.

In one preferred embodiment, the SCBI includes the following dimensionsin inches: body 12 height is 1.75; collar 34 height is 0.36 and collaroutside diameter is 0.602; bottom wall 30 outside diameter is 0.41 andbottom wall 30 inside diameter is 0.38; cap 14 height is 0.81 and capoutside diameter is 0.705

The exemplary embodiments herein disclosed are not intended to beexhaustive or to unnecessarily limit the scope of the invention. Theexemplary embodiments were chosen and described in order to explain theprinciples of the present invention so that others skilled in the artmay practice the invention. As will be apparent to one skilled in theart, various modifications can be made within the scope of the aforesaiddescription. Such modifications being within the ability of one skilledin the art form a part of the present invention and are embraced by theappended claims.

It is claimed:
 1. A method of determining the accuracy of asterilization or decontamination process in a sterilization chambercomprising the steps of: placing a self-contained biological indicator(SCBI) in said sterilization chamber in an open position wherein asterilant gas will enter said SCBI; said SCBI comprising a body adaptedto serve as a culture tube, said body having a cylindrical side wallwhich does not contain any recessed areas, a bottom wall at one end ofthe cylindrical side wall closing the body, a collar at the other end ofthe cylindrical side wall extending outwardly from the cylindrical sidewall having an open end having an interior diameter greater than aninterior diameter of the cylindrical side wall and adapted to receive acap, said collar including a plurality of inwardly extending ribs; a capadapted to engage said body in an open position and a closed position,said cap including a top wall and a cylindrical side wall adapted toengage said collar of said body, said cylindrical side wall including aplurality of apertures; a rupturable glass ampoule including a growthmedia in said body; and a stainless steel disc inoculated with spores ontop of said glass ampoule and adjacent said plurality of ribs;subjecting said sterilization chamber to said sterilant gas; removingsaid SCBI from said sterilization chamber; rupturing said glass ampoulein said SCBI to release said growth media to said body of said SCBI,wherein said stainless steel disc is adapted to drop down into saidcylindrical side wall of said body to contact said inoculated sporeswith said growth media; and closing said SCBI and determining theaccuracy of said sterilization process or said decontamination process.2. A method according to claim 1 wherein said sterilant gas is selectedfrom the group consisting of hydrogen peroxide gas, chlorine dioxide gasand nitrogen dioxide gas.
 3. A method according to claim 1 wherein saidplurality of inwardly extending ribs extend the horizontal length ofsaid collar and are substantially even with the inside wall of saidcylindrical side wall of said body.
 4. A method according to claim 3wherein said plurality of ribs comprise twelve ribs.
 5. A methodaccording to claim 1 wherein said plurality of ribs are adapted to allowair flow of said sterilant gas down the side of said body towards thebottom of said body.
 6. A method according to claim 1 wherein saidgrowth media is a formulated soybean casein digest culture medium.
 7. Amethod according to claim 1 wherein said plurality of apertures of saidcylindrical side wall of said cap comprise six to eight apertures.
 8. Amethod according to claim 1 wherein said cap includes an annular grooveon the inside of said cylindrical side wall and said collar of said bodyincludes upper and lower annular protrusions adapted to engage saidannular groove to hold said cap in open and closed positions.
 9. Amethod of claim 1 further comprising a filter paper covering said disc.10. A self-contained biological indicator comprising: a body adapted toserve as a culture tube, said body having a cylindrical side wall whichdoes not contain any recessed areas, a bottom wall at one end of thecylindrical side wall closing the body, a collar at the other end of thecylindrical side wall extending outwardly from the cylindrical side wallhaving an open end having an interior diameter greater than an interiordiameter of the cylindrical side wall and adapted to receive a cap, saidcollar including a plurality of inwardly extending ribs; a cap adaptedto engage said body in an open position and a closed position, said capincluding a top wall and a cylindrical side wall adapted to engage saidcollar of said body, said cylindrical side wall including a plurality ofapertures; a rupturable glass ampoule including a growth media in saidbody; and a stainless steel disc inoculated with spores on top of saidglass ampoule and adjacent said plurality of ribs.
 11. A self-containedbiological indicator according to claim 10 further comprising a filterpaper covering said stainless steel disc.
 12. A self-containedbiological indicator according to claim 10 wherein said plurality ofinwardly extending ribs extend a horizontal length of said collar andare substantially even with an inside wall of said cylindrical side wallof said body.
 13. A self-contained biological indicator according toclaim 10 wherein said plurality of ribs comprise twelve ribs.
 14. Aself-contained biological indicator according to claim 10 wherein saidplurality of ribs are adapted to allow air flow of a sterilant down theside of said body towards the bottom of said body.
 15. A self-containedbiological indicator according to claim 10 wherein said disc is adaptedto drop down into said body when said glass ampoule is ruptured.
 16. Aself-contained biological indicator according to claim 10 wherein saidgrowth media is a formulated soybean casein digest culture medium.
 17. Aself-contained biological indicator according to claim 10 wherein saidplurality of apertures of said cylindrical side wall of said capcomprise six to eight apertures.
 18. A self-contained biologicalindicator according to claim 10 wherein said cap includes an annulargroove on the inside of said cylindrical side wall and said collar ofsaid body includes upper and lower annular protrusions adapted to engagesaid annular groove to hold said cap in open and closed positions.